About 2,000 commercial water users in the region will, for the first time, need a licence to take water from their dams and bores.

The Adelaide and Mount Lofty Ranges Natural Resources Management Board (NRM) has allocated the wine industry about two megalitres per hectare, but viticulturists say that does not account for differences in soil absorption.

One viticulturist told the ABC that under her current allocation she would have to cut production in half.